A. Field of the Invention
This invention relates generally to the field of lawn sprinklers, irrigation systems, and other systems for water or fluid distribution where parts breakage and/or fluid or pressure loss from the system could be problematic. More particularly, this invention relates to a device which compensates for movement of or impact on water pipes to prevent breakage, and a device which seals off a broken pipe to prevent leakage of any fluid contained therein. An incidental benefit of the invention when applied to lawn sprinklers is that it deters theft of expensive sprinkler heads.
B. The Background Art
In the prior art, substantial problems have been experienced with sprinkler breakage. Lawn sprinkler heads and sprinkler heads used for agricultural irrigation are typically made from brittle plastic and may be easily broken when driven over by an automobile or a lawn mower or even when stepped on. Breakage of a typical prior art sprinkler head results in the sprinkler system sending most of its volume of water through the broken head, flooding the area in that vicinity but leaving the rest of the area to be watered with little or no water. As a result, a great volume of water may be lost through the broken sprinkler head, resulting in damage to the ground in that area from excessive watering and depleting precious water resources in states which experience chronic water shortages. The prior art has demonstrated a need for a device which prevents sprinkler head breakage and a device which directs water flow away from a broken sprinkler head.
Another problem of the prior art is that water pooling around a sprinkler head during lawn watering will tend to drain back into the sprinkler system through the sprinkler head after lawn watering is complete. Such water draining back into the system will carry dirt, grass, stones and other debris with it into the sprinkler system. This dirt will accumulate in a sprinkler system over time clogging the system, including clogging pop-up sprinkler heads so that their pop-up members become stuck in their protruding position and are subject to breakage from vehicles, pedestrian traffic and lawn mowers.
Another problem in the prior art is that expensive sprinkler heads are frequently the target of thieves. In most applications, a sprinkler head may be quickly and easily unscrewed from the sprinkler system and removed. Because of this vulnerability, many parties are unwilling to invest in high quality sprinkler heads. The prior art showed a need for a device which makes removal (and hence theft) of sprinkler heads difficult. The invention provides a device which prevents sprinkler head removal absent digging into the ground beneath the sprinkler head. The additional effort required to remove a sprinkler head from such a device is expected to stop most sprinkler head theft.
An attempt of the prior art to solve the flooding problem of the prior art sprinkler devices is shown in U.S. Pat. No. 5,174,500 issued to Yianilos on Dec. 29, 1992 and is hereby incorporated by reference in its entirety. Yianilos is directed to a sprinkler head assembly that includes a bifurcated member with first and second leg portions and having a sealing means, the sprinkler head assembly being of the fixed or non-pop-up type and the bifurcated member disclosed being adapted specifically for use with such a sprinkler head. The device of Yianilos by its inherent nature would not work with pop-up sprinkler heads because the bifurcated member is not capable of being actuated by a pop-up member and because the device does not include adequate travel to function with a pop-up. Further, the device of Yianilos as described and illustrated functions only when the sprinkler head is completely removed. If the sprinkler head is broken but is not complete removed, the Yianilos device is inoperative and does not prevent sprinkler flooding. If an attempt were made to use the Yianilos device with a pop-up sprinkler head, the Yianilos device would be inoperative because breakage of the pop-up member would not bring about the desired sealing function and flooding would still result. Further, Yianilos does not provide any dual check valve function, a very important feature to prevent entry of dirt into the sprinkler system, sticking of pop-up sprinkler heads and their consequent breakage. The bifurcated member's design inherently prevents downward sealing and hence prevents any dual sealing function. For these reasons, Yianilos fails to solve or even directly address the problems solved by the present invention.
U.S. Pat. No. 5,133,501 issued to Marshall on Jul. 28, 1992, which is hereby incorporated by reference in its entirety, discloses an adjustable riser device for use in sprinkler systems. The device disclosed by Marshall may be selectively adjusted to a variety of fixed heights. The device of Marshall does not, however, remain underground or at ground level until water pressure is present. The device of Marshall is instead fixed in an upright position above the ground and is left in that position, subject to breakage. Further, Marshall provides no ability to move in compensation for force placed on the device to avoid breakage.